grainy footage - underwater shooting

BAJA PRODUCTIONS

BAJA PRODUCTIONS

Member
Hello,
First thanks to all for your answers. I've searched and read most of the threads dealing with noise and grainy footage. What I did not see was anyone posting footage. I'll do so if I can figure out how to do it tonight.

PROBLEM:
shooting underwater first of all. Most of my settings are at 0; gain off, iris manual and adjusted as needed; Shooting in video & filmlike mode; hd normal and cinelike v.

Water conditions: clear and BLUE. with some particles in the water. Some of my footage on the clean water days came out very nice. But others (on days with a bit of particles in the water as well as giant blue backgrounds) came out really grainy.

I was thinking with underwater conditions and blue in the background there might be something I need to set in order to loose the grains. All of the scenes had an animal or person in them....when the subject was centered---they came out very clean with no grains....but around them where the contrast of the subject to blue water began....there began the grainy footage. Especially so when looking in corders of the shot and it was wide open blue ocean.

Any assistance would be greatly appreciated.
 
Did you film underwater ever before? (some physical facts change compared to video over water...)

Do you use a wide-angle lens?

Btw - what housing do you use? - Looks like a Gates housing if that's you on the avatar...

I'll try to check your footage now ...
 
Man that does look very grainy indeed. I've had really good success in shallow water diving and footage. Haven't done anything deeper than 20'. Where were you in relation to the surface? And wow.. you bought that Gates.. So expensive compared to my housing which was custom built...
 
Shoot all of the time, this is a new camera for me and coming from the Sony Z1U....it is a noise box. I think it seems to have a problem in contrast areas and is in need of some fine tuning. But, having control over knee, master pedestal etc...is new to me. Anyone care to chime in on possible settings.
Thanks...
 
Well Baja..


I'd say to shoot in Bpress which is the lowest noise setting.. and definitely go to minus on the master ped and follow Barry G.s advice on low noise setting. If you are leaving it flat then that would be the problem. Ya have to tweek it to get it too look good and I'd use Barry's settings as a guide.. Hope that helps...
 
Thanks, that is what I have done for the moment. I haven't tried underwater, but new settings are:
MP: -7
Bpress

Thanks and I'll update on how it goes with these settings.
 
If I may... I'd suggest that -7 is a little aggressive for your master ped. My suggestion would be to expose as best you can, and then press the shadows in post. If you do -7 on the day you won't get that data back.

My other suggestion would be, stay on the wider side of the lens, and open up the shutter slightly. I would suggest using the shutter angle control and dialing in a setting that is acceptable in terms of chop/streak. Odds are you can push it into the 200-250 range without sacrificing too much, and you'll get a bit more light out of it.

The HVX is only 320 ISO on a good day, so it can be tough with the stuff you're shooting.
 
Yes, use zebras to watch and push your exposure up as far as possible, and don't crush your blacks with b-press. Fix levels and gamma in post. Use a noise filter like the one that ships with AfterEffects, it's perfect for underwater stuff with big washes of color.
If you're actually getting grit in the water, you might have better results with a longer lens, since you can at least get some of the grit out of focus. That's just hypothetical, but it seems to make sense, right?
 
I'm going to try with a few settings....from -4 down on mast ped. and then also with b press and others. I have to stay wide on the lens for 99% underwater so I'll check it out and post results.
thanks for the help
 
Yes, it's a software filter, and can filter noise out using the surrounding pixel data in space as well as time. It takes a lot of tweaking but if the noise isn't overwhelming (think +18dB) you can usually get rid of the apparent noise almost completely, with very little loss of sharpness.
 
I just ordered an Equinox XChaser Mechanical Video Housing with Handles for the Canon HV20. I am planning to take this housing and camera to Cozumel and do some shooting while snorkeling. It will certainly not go near its maximum recommended depth of 45' ... unless I sink.

This camera doesn't have the fancy calibration menus of the professional Canon HD(V) lines, it basically consists of factory presets, although you can adjust the iris.

Can anyone comment on the best presets for this type of underwater videography?
 
Although I am not familiar with that camera, what I do recommend you is to white balance when changing depths. I white balance slate is great for that. But with underwater you will want a slightly blue tinted white slate....amphibico makes them. if you prefer just to shoot and not white balance, then make sure you have something white you can shoot so you can just do an eye drop white balance in your editing program. White balance is the best thing you can do as an amateur shooter. of course before shooting, make sure set your iris. in most cases auto is good enough for most folks. Also shutter speed on auto is best since setting shutter and iris is a challenge for most underwater unless you are setting up a shot. But you will constantly be changing iris and shutter when you change your position to the sun. So you'll just be full of tasks. Good luck
 
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